This paper describes a flexible and lightweight fabric supercapacitor electrode as a possible energy source in smart garments. We examined the electrochemical behavior of porous carbon materials impregnated into woven cotton and polyester fabrics using a traditional printmaking technique (screen printing). The porous structure of such fabrics makes them attractive for supercapacitor applications that need porous films for ion transfer between electrodes. We used cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy to study the capacitive behaviour of carbon materials using nontoxic aqueous electrolytes including sodium sulfate and lithium sulfate. Electrodes coated with activated carbon (YP17) and tested at ∼0.25 A·g−1 achieved a high gravimetric and areal capacitance, an average of 85 F·g−1 on cotton lawn and polyester microfiber, both corresponding to ∼0.43 F·cm−2.

Carbon coated textiles for flexible energy storage

Conductive fabrics usually exhibit two types of electrical resistance: the length-related resistance and contact resistance. The length-related resistance increases with the applied extensile force, whereas the contact resistance decreases with the contact force. The resistance of conductive knitted fabrics could be modeled by the superposition of the length-related resistance and contact resistance. Three experiments were conducted to investigate the resistance of conductive yarns: two overlapped conduct yarns and conductive knitting stitches under unidirectional extensile forces, respectively; and the corresponding empirical equations were developed. The relationship of the resistance, tensile force, fabric length and width were established. The fitting curves with high coefficient of determinations (>0.94) and low standard errors (<0.18) given by the modeling equations were achieved. Therefore, the proposed model could be used to compute the resistance of the conductive knitting fabrics under unidirect...

Electromechanical analysis of length-related resistance and contact resistance of conductive knitted fabrics:

Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.

https://www.mdpi.com/1996-1944/14/12/3390/pdf

The Impact of Elongation on Change in Electrical Resistance of Electrically Conductive Yarns Woven into Fabric

Recently, the demands of the wearable systems and products for monitoring biosignal to manage the health are increased by the increasing interests for introducing an aging society and for the lifestyle of well-being. Global sports brands such as Adidas and Nike tried to enter into the market with the study about the wearable system for measuring the heart-rate, and lately global casual brand of Polo is going to introduce the market expansion with business implementations. However, the studies of textile materials for measuring an electrocardiogram have constantly conducted but the studies for correlation of an electrocardiogram measurement signal by electrode structure and type are insufficient. Therefore, this study developed 8 types of electro-thread by considering the condition of TM and covering based on the silver thread, and developed total 16 type electrodes by consisting two different size of electrode. By comparing and analyzing magnitudes of biosignal and noise according to electrode size when standing with applied the developed electrode into tight sports wears, we evaluated the effectiveness with electrocardiogram measurement electrode by its size. From this case, it derived the correlation of electrode for electrocardiogram measurement and design factors according to the final suitable electro-thread and the electrode size after analyzing signals and noises from standing and walking based on small size electrode that is dominant to measure signals.

Development of textile electrode for electrocardiogram measurement based on conductive electrode configuration

The integration of electronic components in/onto conductive textile yarns without compromising textile qualities such as flexibility, conformability, heat and moisture transfer, and wash resistance is essential to ensuring acceptance of electronic textiles. One solution is creating flexible and stretchable conductive yarns that contain tiny surface-mounted electronic elements embedded at the fiber level. The purpose of this work was to manufacture and subsequently evaluate the physical features and electromechanical properties of stainless steel yarn with light-emitting surface mounted devices (SMDs) embedded in it. The SMDs were successfully integrated into a conductive stainless steel yarn (SS) by inserting crimp beads and creating a bond through hot air soldering machines, resulting in what we call an E-yarn. The relationship curves between gauge length and electrical resistance, and the relationship curves between conductive yarn elongation and electrical resistance, were explored experimentally. The results of the analysis demonstrated that E-yarn had a lower tensile strength than the original electrically-conductive SS yarn. The effects of the washing cycle on the conductivity of the E-yarn were also investigated and studied. The results showed that E-yarns encapsulated at the solder pad by heat shrink tube still functioned well after ten machine wash cycles, after which they degraded greatly.

/pdf/development-of-stainless-steel-yarn-with-embedded-surface-v5h7e90r.pdf

Development of Stainless Steel Yarn with Embedded Surface Mounted Light Emitting Diodes

In this study, the theoretical resistance of silver coated conductive yarn which occurs through physical stimuli applied during weaving and clothing making processes was investigated and compared to experimental resistance. Resistance change of silver coated conductive yarn was also analyzed. The theoretical resistance suggested in previous studies is different to the experimental resistance in this study. It was confirmed that, as strain increases, resistance by splitting and separation of the silver coating particles increases and as the contact area among filaments increases, resistance decreases. Influential factors for separation of silver coating particles and contact factors were expressed as equations. Based on these equations, a final equation was derived and it was confirmed that theoretical resistance and experimental resistance have similar increasing tendency. Therefore, resistance change according to length increases of silver coated nylon 6.6 in each strain interval is predictable. Supercritical Fluid-assisted Electroless Copper Plating of Aramid Film: The Influence of Surface Treatment Magali Belma, Isao Tabata, Kenji Hisada, and Teruo Hori Graduate School of Engineering, Fiber Amenity Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 Japan Technical Department, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan Abstract: A process of metalizing aramid fibers using supercritical CO2 (sc-CO2) followed by electroless copper plating has been developed recently. However, some applications require larger conductive surfaces without losing any of aramid fibers qualities (heat and chemical resistance, high strength, high flexibility). In response to such requirements, we developed in our present study a method of plating aramid film after impregnating it with organometallic complexes using sc-CO2 as a medium. In order to achieve uniform plating coupled with a high adhesiveness of the plated layer, two factors were examined. The impregnated Pd was reduced by two agents, NaBH4 in aqueous solution and H2 gas, in order to increase the amount of Pd metal present on the film surface. We found that the reduction of Pd did improve the plating of the aramid film. In spite of this, the adhesion of the shiny copper-colored layer had low strength. Effects of Ultraviolet Radiation on the Color of Compounded Papers Containing Wasted Tea Leaves Tetsuya Takahashi, Wakako Kasai, and Tetsuo Kondo Faculty of Education, Shimane University, 1060 Nishikawatsu-cho, Matsue, Shimane, 690-8504, Japan Bio-Architecture Center, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Abstract: Influence of ultraviolet irradiation on papers containing wasted tea leaves was studied. Ultraviolet irradiation generally caused reddish coloration. Irradiation under dry atmosphere caused stronger coloration than under ambient conditions. Presence of oxygen did not cause significant difference in coloration. Thin-layer chromatographic analysis showed disappearance of chlorophylls a and b, and did not disappearance of theaflavin by UV irradiation. The results strongly suggest that the coloration is caused by photochemical conversions of catechins to reactants (theaflavin-like compounds). Influence of ultraviolet irradiation on papers containing wasted tea leaves was studied. Ultraviolet irradiation generally caused reddish coloration. Irradiation under dry atmosphere caused stronger coloration than under ambient conditions. Presence of oxygen did not cause significant difference in coloration. Thin-layer chromatographic analysis showed disappearance of chlorophylls a and b, and did not disappearance of theaflavin by UV irradiation. The results strongly suggest that the coloration is caused by photochemical conversions of catechins to reactants (theaflavin-like compounds). 1748 Textile Research Journal 80(16) TRJ

Effect of Strain Change of Electrically Conductive Yarn on Electric Resistance and Its Theoretical Analysis

Recently, study of functional clothing for vital sensing is focused on improving conductivity and decreasingresistance, in order to enhance the electrocardiogram(ECG) sensing accuracy and obtained stable environmental durab ility onoperation condition. In this study, four ECG fabrics that having different componnt yarns and weaving structures were produced toanalyze their environmental durabilities and electric properties under general operation cond itions including different physical andchemical stimulation. For outstanding electric properties and physical properties, the optimized ECG sensing fabric should consist ofa fabric of 2 up 3 down twill structure containing 210de silver-coated conductive yarns and polyester yarn in warp and weftdirections respectively. The selected fabric has 0.11 which is relative lower resistance than otherwisely produced fabrics underΩECG measurement condition. And it has 7% stable resistance changes under 25% strain and repeated strain. Keywords:

/pdf/basic-study-of-weaving-structure-and-durability-for-fabric-h820gonjyc.pdf

Hong-Jae Kim

Papers

Effect of Strain Change of Electrically Conductive Yarn on Electric Resistance and Its Theoretical Analysis

Basic Study of Weaving Structure and Durability for Fabric-type ECG Sensor Design